This invention relates to the selective placarding of vehicles. More particularly, this invention relates to vehicle placarding apparatus which provides for convenient changes of the indication of cargo contents.
Motor and rail vehicles have long been placarded to indicate the nature or contents of cargo carried by the vehicle. Known placarding means include imprinted, adhesive backed cards pasted to the vehicle and imprinted plates mechanically attached to the vehicle by bolts, rivets or the like. These placarding means have a disadvantage in that the placarding cannot be rapidly and economically changed to reflect the often frequent changes in the vehicle cargo.
Another known placarding system provides an elongated rectangular inscription area formed by a plurality of generally rectangular plates with their transverse edges hinged at a bisector of the elongated rectangle so that the plates may be turned like the pages of a book to change the placarded inscription. Multiple spring clips mounted on a rigid base member are located at cutaway corners of both transverse edges of the elongated rectangle to selectively maintain the plates in position against the rigid base member. A raised ledge is integral with the base member along the edges thereof parallel to the elongate rectangle edges, but the transverse edges of the base member are flat.
Recently, the Department of Transportation has promulgated new requirements for the placarding of vehicles carrying hazardous materials in commerce. Those requirements, set out in Vol. 41, No. 74 of the Federal Register, Apr. 15, 1976, prescribe that a diamond-shaped placard of specified dimensions be affixed to the front, rear and sides of vehicles carrying hazardous materials.
It would be desirable to provide a placarding system that would meet those requirements while providing for changes of the placard inscription.
The new requirements present particular difficulty with respect to the placarding of vehicles having roll-up doors, which may include the entire rear vertical surface of the vehicle available for placarding. The difficulty results because the diagonal length of the diamond-shaped placard now required in most cases exceeds the height of the hinged rectangular sections which normally comprise the roll-up doors. Hence, known rigid, planar placards, reconfigured in a diamond-shape, cannot be used on roll-up doors, since they interfere with the operation of the door. Accordingly, it would be desirable to provide a diamond-shaped placarding apparatus suitable for use with roll-up vehicle doors.